10.1021/jacs.8b11395.s001Xiao-Hui YangRyan T. DavisonShao-Zhen NieFaben A. CruzTristan M. McGinnisVy M. DongCatalytic
Hydrothiolation: Counterion-Controlled Regioselectivity2019American Chemical SocietydependencedieneRh complexespathwayhydroMarkovnikovcounterionhomoallylic sulfidesregiothiol2019-02-08 19:49:02articlehttps://acs.figshare.com/articles/Catalytic_Hydrothiolation_Counterion-Controlled_Regioselectivity/7697867In
this Article, we expand upon the catalytic hydro­thiolation
of 1,3-dienes to afford either allylic or homoallylic sulfides with
high regio­control. Mechanistic studies support a pathway in
which regio­selectivity is dictated by the choice of counterion
associated with the Rh center. Non-coordinating counterions, such
as SbF<sub>6</sub><sup>–</sup>, allow for η<sup>4</sup>-diene coordination to Rh complexes and result in allylic sulfides.
In contrast, coordinating counterions, such as Cl<sup>–</sup>, favor neutral Rh complexes in which the diene binds η<sup>2</sup> to afford homoallylic sulfides. We propose mechanisms that
rationalize a fractional dependence on thiol for the 1,2-Markovnikov
hydro­thiolation while accounting for an inverse dependence on
thiol in the 3,4-<i>anti</i>-Markovnikov pathway. Through
the hydro­thiolation of an essential oil (β-farnesene),
we achieve the first enantio­selective synthesis of (−)-agelasidine
A.